Camera Integral With Optical Fiber

ABSTRACT

A camera ( 1 ) has a tubular housing ( 3 ) having an emission window ( 7 ). A unitized optical fiber bundle ( 9 ) is provided on the inner surface of the housing ( 3 ) by utilizing a bundle of light guiding optical fibers on the inner surface. The unitized optical fiber bundle ( 9 ) is placed on and bonded to the inner surface of the housing ( 3 ) with the fibers bonded together by a bonding agent. An end section of the unitized optical fiber bundle ( 9 ) reaches the emission window ( 7 ) of the housing ( 3 ) to be exposed. The camera ( 1 ) has sufficient waterproof capability and is easy to produce, and capable of avoiding a decrease in the amount of light.

TECHNICAL FIELD

The present invention relates to a camera integral with optical fibers.

BACKGROUND ART

Conventionally, a camera integral with optical fibers is used, forexample, for dental or other medical uses. This kind of camera isrequired to be small, as well as to light up an area to be treated. Inorder to meet these requirements, a camera is provided with anillumination device using optical fibers. Such a camera is disclosed,for example, in Japanese laid-open publication No. Hei. 8-332170A (pages3 to 4, and FIG. 1).

FIG. 11 shows a front-end part of a conventional camera integral withoptical fibers. A camera 101 has a tubular housing 103, in which a CCDor other imaging devices and an image processing circuit are housed. Onthe side of the front end of the housing 103 is provided a shootingwindow 105, in which a prism is inserted. Light that enters through theshooting window 105 is bent by the prism and guided in the tubedirection. Emission windows 107 are placed as an illumination device onboth sides of the shooting window 105.

FIG. 12 is a cross section of the camera of FIG. 11. As shown in thefigure, an optical fiber component 109 is fixed in the housing 103. Theoptical fiber component 109 is an aggregate of thin fibers. Many thinfibers are bundled with a front-end fitting 111 and hardened by abonding agent, thus producing the part having the configuration shown inthe figure. This separate part, the optical fiber component 109, isfixed in the housing 103 by hand.

In the assembling work, the optical fiber component 109 is inserted intothe housing 103 from behind so that the front-end fitting 111 goesfarther and farther into the housing 103, and then the front-end fitting111 is placed near the emission window 107. When used, the optical fibercomponent 109 guides illumination light, which is then emitted from theemission window 107.

Additionally, sapphire glass is inserted in and bonded to the emissionwindow 107, thus ensuring sufficient waterproof capability.

As described above, the optical fiber component, that is a separatecomponent bundled with the front-end fitting, is fixed to theconventional camera integral with optical fibers. For this reason, it isnot easy to form the part using the fitting, to incorporate the part,and to incorporate the optical fiber component into the housing. Inaddition, since the sapphire glass for waterproof use is inserted in theemission window 107 in the conventional camera integral with opticalfibers, light emitted from the optical fibers is reflected off thesapphire glass. Consequently, the amount of light decreases by theamount corresponding to the reflection.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

A purpose of the invention made in the above-mentioned background is toprovide a camera integral with optical fibers that has sufficientwaterproof capability, is easy to produce, and prevents a decrease inthe amount of light.

Means for Solving the Problems

A camera integral with optical fibers of the invention comprises: atubular housing having an emission window; and a unitized optical fiberbundle which is a bundle of light guiding optical fibers unitized on aninner surface of the housing, wherein the unitized optical fiber bundleis provided on and bonded to the inner surface of the housing with thefibers bonded together by a bonding agent, and wherein an end section ofthe unitized optical fiber bundle reaches the emission window to beexposed.

There are other aspects of the invention as described below. Thisdisclosure of the invention therefore intends to provide part of aspectsof the invention and does not intend to limit the scope of the inventiondescribed and claimed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section of a camera integral with optical fibersaccording to an embodiment of the invention;

FIG. 2 shows a perspective view of the camera integral with opticalfibers according to the embodiment of the invention;

FIG. 3 shows a housing and optical fibers of the camera integral withoptical fibers according to the embodiment of the invention;

FIG. 4 shows a step of inserting optical fibers in a method of producingthe camera integral with optical fibers according to the embodiment ofthe invention;

FIG. 5 shows a step of molding a fiber bundle in the method of producingthe camera integral with optical fibers according to the embodiment ofthe invention;

FIG. 6 shows the step of molding the fiber bundle in the method ofproducing the camera integral with optical fibers according to theembodiment of the invention;

FIG. 7 shows the step of molding the fiber bundle in the method ofproducing the camera integral with optical fibers according to theembodiment of the invention;

FIG. 8 shows a step of grinding an emission window in the method ofproducing the camera integral with optical fibers according to theembodiment of the invention;

FIG. 9 shows a step of attaching a silicone tube in the method ofproducing the camera integral with optical fibers according to theembodiment of the invention;

FIG. 10 shows a step of cutting an insert pipe in the method ofproducing the camera integral with optical fibers according to theembodiment of the invention;

FIG. 11 is a perspective view showing a configuration example of aconventional camera integral with optical fibers; and

FIG. 12 is a cross-sectional view showing the configuration example ofthe conventional camera integral with optical fibers.

DESCRIPTION OF THE SYMBOLS

-   -   1: camera    -   3: housing    -   5: shooting window    -   7: emission window    -   9: unitized optical fiber bundle    -   11: inner surface    -   13: end section    -   15: exposed section    -   17: housing surface    -   19: rear section    -   21: optical fiber bundle    -   23: silicone tube    -   25: insert pipe    -   27: rear end    -   29: rear opening    -   31: inner mold    -   33: outer mold

BEST MODE OF EMBODYING THE INVENTION

Now, the invention will be described in detail. However, the followingdetailed description and appended drawings are not intended to limit theinvention. Alternatively, the scope of the invention is defined by theappended claims.

A camera integral with optical fibers of this embodiment comprises: atubular housing having an emission window; and a unitized optical fiberbundle which is a bundle of light guiding optical fibers unitized on aninner surface of the housing, wherein the unitized optical fiber bundleis provided on and bonded to the inner surface of the housing with thefibers bonded together by a bonding agent, and wherein an end section ofthe unitized optical fiber bundle reaches the emission window to beexposed.

In this configuration, since the above unitized optical fiber bundle, abundle of optical fibers unitized on the inner surface of the housing,is provided, optical fibers as a separate component bundled with afront-end fitting can be eliminated, and the assembly work of fixingoptical fibers becomes unnecessary. Consequently, the production becomeseasy. In addition, the end section of the unitized optical fiber bundleexposed directly from the housing allows conventional sapphire glass tobe eliminated, while ensuring sufficient waterproof capability. Adecrease in the amount of light caused by sapphire glass can thereforebe avoided. In this way, a camera integral with optical fibers can beprovided that has sufficient waterproof capability, is easy to produce,and prevents a decrease in the amount of light.

In this camera integral with optical fibers, an exposed surface of theunitized optical fiber bundle in the emission window is on the samelevel with a surrounding housing surface.

In this configuration, a structure can be easily produced in which anend section of the unitized optical fiber bundle is exposed from thehousing. The exposed surface of the unitized optical fiber bundle mayhave a common work surface with the surrounding housing surface.

As described above, the camera integral with optical fibers having theabove configuration carries the advantage that it has sufficientwaterproof capability, is easy to produce, and can avoid a decrease inthe amount of light.

Another aspect of the invention is a method of producing a component ofthe camera integral with optical fibers. This method will also bedescribed in the embodiment. This method brings the advantage offacilitating the production of the component of the camera integral withoptical fibers.

Now, the camera integral with optical fibers of the embodiment of theinvention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a camera integral with opticalfibers of an embodiment of the invention, and FIG. 2 is a perspectiveview of its external appearance. As shown in FIG. 2, a camera 1 isalmost the same in appearance as conventional cameras. The camera 1 hasa tubular housing 3, which is a stainless-steel camera case. In thehousing 3 are housed a CCD or other imaging device and an imageprocessing circuit. On the side of the front end of the housing 3 isprovided a shooting window 5, in which a prism is inserted. Light thatenters through the shooting window 5 is bent by the prism and guided inthe tube direction (hereinafter meaning the longitudinal direction ofthe tube), and reaches the imaging device through an optical system.Emission windows 7 are placed as an illumination device on both sides ofthe shooting window 5.

In the cross section of FIG. 1, the housing 3 incorporates a bundle ofoptical fibers. In the embodiment, the bundle of optical fibers isunitized on the inner surface of the housing. This bundle of opticalfibers is called the “unitized optical fiber bundle.” One optical fiberis, for example, 30 micrometers in diameter. The unitized optical fiberbundle 9 therefore comprises a great many optical fibers.

The unitized optical fiber bundle 9 is placed like a membrane on aninner surface 11 of the housing 3. The unitized optical fiber bundle 9comprises a lot of thin optical fibers, which are bonded to the innersurface 11 with the fibers bonded together by a bonding agent. Thoughnot shown in FIG. 1, the unitized optical fiber bundle 9 is divided intotwo halves corresponding to the two emission windows 7. Each half coversapproximately half of the inner surface 11 of the housing 3.

In the housing 3, the unitized optical fiber bundle 9 is provided in thetube direction, and is bent in the front-end part of the housing 3toward the emission window 7. Actually, each one of the optical fibersis bent in the bent section. In addition, the cross-sectional shape ofthe unitized optical fiber bundle 9 changes in the bent section. Thatis, the cross-sectional shape changes from the membrane-like shaperunning along the inner surface of the housing 3 to an approximatelyrectangular shape spreading along the emission window 7.

An end section 13 of the unitized optical fiber bundle 9 reaches theemission window 7 of the housing 3 to be exposed. The end section 13 isfull of many optical fibers, and a bonding agent is filled between eachof the optical fibers. This configuration ensures sufficient waterproofcapability. At the emission window 7, an exposed surface (end surface)of an exposed section 15 of the unitized optical fiber bundle 9 isenclosed by a housing surface 17 surrounding the exposed surface, andthe exposed surface (end surface) is a common work surface with thesurrounding housing surface 17. Consequently, the exposed surface (endsurface) is on the same level with the surrounding housing surface 17.

FIG. 3 shows the housing 3 as one component comprising the unitizedoptical fiber bundle 9. Rear sections 19 of the unitized optical fiberbundle 9 protrude from the rear of the housing 3. In the followingdescription, the rear means a direction away from the front end alongthe tube direction of the housing 3.

As previously described, the unitized optical fiber bundle 9 is dividedinto two halves in the housing 3, and each half covers approximatelyhalf of the housing 3. Corresponding to this configuration, the two rearsections 19 are also seen at the rear of the housing 3. As with thefibers in the housing 3, each rear section 19 is molded like a membrane.

In a completed camera, the rear section 19 is housed in another housing,not shown, in the rear. The rear housing is coupled to the housing 3,and is larger in outer diameter than the housing 3. The rear housingalso incorporates a substrate and a light source. Additionally, animaging cable extends from the rear housing.

Rear sections further behind the rear sections 19 of the unitizedoptical fiber bundle 9 are not-yet bonded optical fiber bundles 21 (Therear section 19 may be called a middle section, and alternatively therear section behind the rear section 19 may be called a rear section.The rear section behind the rear section 19 may also be called a tailsection). The optical fiber bundle 21 is bundled here with a siliconetube 23. The optical fiber bundles 21 are then inserted into an insertpipe 25 in the rear of the silicone tubes 23. The optical fiber bundles21, divided into two, join together at the insert pipe 25.

On a rear end 27 of the insert pipe 25 is formed a common ground surfaceof the insert pipe 25 and the optical fiber bundles 21. Though not shownin the figure, light emitted from the light source is guided by anotheroptical fiber and then passed on through the rear end 27 of the insertpipe 25. The light is then guided through the unitized optical fiberbundle 9 to the front end of the camera, and is emitted from theemission window 7. The two-way split structure provided in the lightguide system facilitates parts replacement at the time of trouble, andcan therefore improve serviceability.

A method of producing the camera integral with optical fibers of theembodiment will be described next. As shown in FIG. 4, the not-yetbonded optical fiber bundle 21 is inserted into the housing 3 in thefirst place. An optical fiber is, for example, approximately 30micrometers in diameter, so a great many optical fibers are inserted.The optical fiber bundle 21 is inserted from the emission window 7 andcomes out from a rear opening 29 of the housing 3. At this time, eachfiber of the optical fiber bundle 21 bends in the housing 3. As shown inthe figure, the optical fiber bundle 21 thus goes through the housing 3and protrudes from the emission window 7 and from the rear opening 29.

As shown in FIG. 5, a bonding agent is applied to part to be unitized ofthe optical fiber bundle 21. The application area is an areacorresponding to the above-described unitized optical fiber bundle 9.The bonding agent is also applied to an area corresponding to the rearsection 19. The bonding agent is, for example, a thermosetting siliconeadhesive. FIG. 5 also shows that an inner mold 31 is attached to thehousing 3. An outer mold 33 is then attached around the inner mold 31.

The inner mold 31 is a rod-like member that corresponds to a core. Theinner mold 31 is inserted into the housing 3. In the state where it isinserted, a gap is formed between the inner surface 11 of the housing 3and the inner mold 31. The shape of the gap corresponds to the unitizedoptical fiber bundle 9 to be molded. The optical fiber bundles 21 withthe bonding agent applied thereto are put in this gap. In an area wherethe unitized optical fiber bundle 9 is not formed, the inner mold 31 isshaped so that it is in close contact with the housing 3. Thisclose-contact section locates the inner mold 31 against the housing 3.

The outer mold 33 has a cylindrical shape. The outer mold 33 is attachedin a state where the inner mold 31 is inserted into the housing 3. Theouter mold 33 is attached around part of the inner mold 31 whichprotrudes from the housing 3. As shown in the figure, the outer mold 33has a two-division structure, and the two halves are put together.

The outer mold 33 forms a gap with the inner mold 31. The shape of thisgap corresponds to the rear sections 19 of the unitized optical fiberbundle 9. Part of the optical fiber bundle 21 that protrudes toward therear from the housing 3 is put in this gap. However, the inner mold 31is in close contact with the outer mold 33 in some upper and lowersections. The optical fiber bundles 21 do not get into theseclose-contact sections. This also corresponds to the above-describedtwo-division structure of the rear sections 19.

Referring to FIG. 6, the bonding agent is cured in the state where theinner mold 31 and the outer mold 33 are attached. For example, the cureprocess is performed at a temperature of 80 degrees Celsius for twohours. After the cure, the outer mold 33 and the inner mold 31 areremoved as shown in FIG. 7. The optical fiber bundles 21 are bonded likea membrane on the inner surface 11 of the housing 3 and unitized withthe housing 3 to be the unitized optical fiber bundle 9. The rearsections 19 of the unitized optical fiber bundle 9 are also molded likea membrane as a result of being put between the inner mold 31 and theouter mold 33. The rear sections 19 protrude from the rear of thehousing 3. In the rear further behind the rear sections 19, the opticalfibers are still free and separated from each other since the bondingagent was not applied thereto.

In the next step, part of the optical fiber bundle 21 that protrudesfrom the emission window 7 is cut off as shown in FIG. 8. An end sectionof the optical fiber bundle 21 is first cut leaving approximately 2 mm.This 2 mm section is then cut off by grinding. In the grinding process,the optical fiber bundle 21 is ground together with the housing surface17 surrounding the emission window 7. As a result, the exposed section15 of the end section 13 of the unitized optical fiber bundle 9 becomesa surface that is on exactly the same level with the surrounding housingsurface 17. The housing 3 is subjected to a blast treatment after thegrinding.

As shown in FIG. 9, part of the optical fiber bundle 21 is left not-yetbonded in the rear sections further behind the rear sections 19 of theunitized optical fiber bundle 9. This part of the optical fiber bundle21 is drawn through the silicone tube 23 to be bundled. The siliconetube 23 circularly bundles the optical fiber bundle 21 by heatshrinkage. In addition, as shown in FIG. 10, the optical fiber bundle 21is inserted into and bonded to the insert pipe 25 in the rear of thesilicone tube 23. The optical fiber bundles 21, divided into two, jointogether at this insert pipe 25. The rear end 27 of the insert pipe 25is then ground together with the optical fiber bundle 21 inside.

In this way, optical fibers are unitized with the housing 3. A prism isinserted into the shooting window 5 of the housing 3. The housing 3 isalso coupled with another housing in the rear (see FIG. 2). It furtherincorporates an imaging device, a substrate, a light source, an imagingcable, and other various components, so that the camera 1 is brought tocompletion.

As described above, the camera integral with optical fibers 1 of theembodiment is provided with the light-guiding unitized optical fiberbundle 9 unitized on the inner surface of the housing, and thereforeoptical fibers as a separate component bundled with a front-end fittingcan be eliminated. The assembly work of fixing optical fibers becomesunnecessary. Consequently, the production becomes easy. In addition, theend section of the unitized optical fiber bundle 9 is exposed directlyfrom the emission window 7 of the housing 3. As a result, conventionalsapphire glass can be eliminated while sufficient waterproof capabilityis ensured. A decrease in the amount of light caused by sapphire glasscan therefore be avoided. In this way, the camera integral with opticalfibers 1 can be provided that has sufficient waterproof capability, iseasy to produce, and prevents a decrease in the amount of light.

Additionally, in the camera integral with optical fibers 1 of theembodiment, the optical fiber bundle is placed like a membrane on theinner surface of the housing and bonded thereto. The optical fiber nottaking up much space also has an advantage in miniaturization, and cancontribute to a reduction in the diameter of the camera.

Moreover, in the camera integral with optical fibers 1 of theembodiment, the exposed surface of the unitized optical fiber bundle 9in the emission window is on the same level with the surrounding housingsurface, so that the structure can be easily provided in which the endsection of the unitized optical fiber bundle 9 is exposed from thehousing. In the above example, the both surfaces are worked at a time.

Furthermore, a method of producing the camera integral with opticalfibers and a component thereof has been described in the aboveembodiment. Another aspect of the invention is such a method ofproducing the camera integral with optical fibers or a componentthereof. In the above example, the inner mold is used and the unitizedoptical fiber bundle is suitably formed. The above method can eliminatean optical fiber bundle as a separate component bundled with a front-endfitting. The assembly work of fixing optical fibers therefore becomesunnecessary. Consequently, the production becomes easy.

While there has been described what are at present considered to bepreferred embodiments of the invention, it will be understood thatvarious modifications may be made thereto, and it is intended thatappended claims cover all such modifications as fall within the truespirit and scope of the invention.

INDUSTRIAL APPLICABILITY

The invention has advantages that it ensures sufficient waterproofcapability, is easy to produce, and can avoid a decrease in the amountof light, and it is useful as a camera for dentists or the like.

1. A camera integral with optical fibers, said camera comprising: atubular housing having an emission window; and a unitized optical fiberbundle which is a bundle of light guiding optical fibers unitized on aninner surface of said housing, wherein said unitized optical fiberbundle is provided on and bonded to said inner surface of said housingwith said fibers bonded together by a bonding agent, and wherein an endsection of said unitized optical fiber bundle reaches said emissionwindow to be exposed.
 2. The camera integral with optical fibersaccording to claim 1, wherein an exposed surface of said unitizedoptical fiber bundle in said emission window is on the same level with asurrounding surface of said housing.